Different types of eolian systems are known which are based on the strength of the wind applied to blades vertically mounted over a flexible and closed transmission belt running between columns, by means of their corresponding pulleys, such that the strength of the wind impinging on the blades involves them being pushed and, as a result, the dragging of the transmission belt, to be able to apply the kinetic energy created by the movement to the pumping of water or air, the driving of mills or other machines or to supply alternators to produce electric energy.
A system of this type is that claimed in the Spanish patent No. 9401773, of the same applicant, which is based on a series of blades having a bi-convex profile, which are transversely joined, across some distancing components, to a flexible transmission belt, specifically consisting of two or more cables in a horizontal arrangement and at different heights, cables which run over pulleys, in turn arranged in a series of columns or towers, pulleys which are assembled on alternator shafts, such that movement in the closed circuit of the transmission belt formed by the cables is converted into a rotational movement by the pulleys and hence in a movement of the alternator shaft to produce electric energy.
These types of systems are or a fixed pitch, that is, the relative position between the cables of the transmission belt and the blade profile axis remains constant such that the wind impact angle at the blade depends on the ratio of blade and wind speeds, it being necessary to use mechanisms which vary the speed of the blades to select an impact angle and hence be able to adjust the wind motor power. On the other hand, the wind impact angle over the blade profile when the turbine is idle is inadequate for motor effects to be produced on them and, therefore, the system cannot start by itself. Finally, when extremely strong winds or gales blow, the blades are subjected to very large stresses, it being possible, on certain occasions, that they suffer considerable damage or complete destruction.
Another system with same characteristics is that described in Patent GS-A-403 607, which discloses the possibility of changing the position of the blades with the assistance of a regulator associated to one of the two shafts and to an auxiliary chain which brings about a change in the leading angle of all the blades with the assistance of short rods.
Although this system entails in itself a remarkable advancement in optimising performance, it is however more complex and furthermore provides a mayor drawback or disadvantage in that the change in the leading angle of the blades is the same for all of them.